If dictionary files have changed, reload them

Hi,

I tried sending you an email about this yesterday, but then I decided this might be a good time for me to learn how GitHub works, with forks and pull requests and such.

Here are modifications to Hunspell.java, to take care of the "Todo" about detecting if the dictionary files have changed.

I created a second HashMap to keep the modified date of the .dic and .aff files (added together). Every time getDictionary(...) is called, the modified date gets checked again and if it has changed, it destroys that dictionary instance and reloads it.

Jeremy